Getting datatype other than colour from pixels

Programming Questions

velvetkev..

Getting datatype other than colour from pixels

in Programming Questions • 2 years ago

Hi folks,

I'm working on some pieces to generate sound from the shape or form of an image, and I've got them working quite nicely using X and Y points. What I would like to try is to have the colour value of each pixel influence the output; its simple to get the colour of each using get(x, y) or similar, but is there a method to extract a value (an int or float) from each pixel?

Thanks in advance

Kyle

Replies(5)

glasshopp..

Re: Getting datatype other than colour from pixels

2 years ago

Here you go - this should answer your question. The following code loads an image loops through its pixels array and prints the result to the console. Have fun.

/**
* Color Sniff - by Glasshopper.
* Grab an image - loads its pixels array and print each pixels colour - at lightening speed
*/
PImage img;
int wh;
color myColors[];
void setup() {
size(100,600,JAVA2D);
//println(width*blockSize);
//println(height*blockSize);
noStroke();
background(0);
// load your image png/gif/jpg etc
img = loadImage("1.png");
wh = img.width*img.height;
img.loadPixels();
myColors = new color[wh];
for (int i=0; i < wh; i++) {
// print the color value - do what you want with it
println(img.pixels[i]);
}
exit();
}

PhiLho

Re: Getting datatype other than colour from pixels

2 years ago

I am not sure I fully understood the question, but for your information, in Processing, 'color' is actually a simple int.

cedrickie..

Re: Getting datatype other than colour from pixels

2 years ago

from a pixel you get the color. i guess the question is what information can be extracted from a color.
there is red(), green(), blue(), brightnes(), saturation() and hue() that quickly comes to my mind. probably some more depening what you want to analyze

velvetkev..

Re: Re: Getting datatype other than colour from pixels

2 years ago

Ah, that's exactly what I was looking for, cedrickiefer. Thanks!

Glasshopper, thanks for putting that together. Out of interest, can anyone clarify how the numbers generated by the code above relate to colours? It seems to be a single number of up to eight digits per pixel, where a white pixel returns -1, but obviously this is different to how we approach it in code- I assume this is the int that phi.lho is referring to?

Thanks again

Kyle

PhiLho

Re: Getting datatype other than colour from pixels

2 years ago

You should read a bit on color type. In short, most colors are negative because the alpha component (including the high bit, sign bit) is not zero, ie. they are opaque.

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